ATL: TROPICAL DEPRESSION HENRI (10L)

[Aric Dunn]

Good news

they may downgrade but by no means is it dead.. ..

we will probably see a new burst sometime here soon.. and actually the multiple vorts explains why there has not been a burst of convection near the naked swirl and thats because the vort that was under the convection is where all the convergence is.


http://www.ssd.noaa.gov/goes/flt/t1/loop-rgb.html

[HURAKAN]

Loop

[Evil Jeremy]

Should be down to a TD at 5, dead at 11 at this rate unless something drastic happens soon.

[Aric Dunn]

Shear is dropping very quickly now that the ULL is weakening and moving ever so slowly wsw to sw... the shear axis is becoming less defined and needs to be watched for it to fade away as the ULL dies .. that would allow for a period of more favorable conditions..

[Aric Dunn]

Should be down to a TD at 5, dead at 11 at this rate unless something drastic happens soon.

hehe convective burst soon a little closer the center.. should occur.. low level clouds are thickening again..

[tailgater]

Is that the primary circulation or there may be another one under the convection? I ask as I see some inflow towards the convection.

actually thats exactly what it is .. as you can see another vort just got spit out from the convection!! both are rotating around a mean center that is slightly closer to the convection ..

From what I can see on the visible loop that is the only center as of now and seems to be getting a bit more inflow as the day goes on, I'd would expect a refire near the center later this evening.

[Cuber]

KF CP = Kentucky Fried Chicken People? That's just what popped into my head first. Must be lunch time.

LOL

ProMets laughing out loud and admitting to thinking about lunch during tropical storm/cyclone season ??? more evidence of a hum-drum 2009 (but keep your waders and slicker nearby Gusty ... just in case)

[wxman57]

Is that the primary circulation or there may be another one under the convection? I ask as I see some inflow towards the convection.

actually thats exactly what it is .. as you can see another vort just got spit out from the convection!! both are rotating around a mean center that is slightly closer to the convection ..

From what I can see on the visible loop that is the only center as of now and seems to be getting a bit more inflow as the day goes on, I'd would expect a refire near the center later this evening.

Yes, that's the only center but I don't see increasing inflow. Just the opposite, I see it's weakening as it separates farther and farther from the convection in an environment of increasing shear.

[wxman57]

Here's an interesting satellite shot/surface plot. Look at the pressure readings and winds around Henri. Note where the highest pressures on the map are - closer to Henri. Now it could be that the ship south of Henri has a barometer that needs recalibration. Look at the pressure gradient from near the center to just east of the heavier squalls - about zero. So there really doesn't appear to be anything present to produce TS winds. Maybe not even 30kt winds. I can't believe that the central pressure of that small vortex is 1008mb. That great of a pressure gradient (8 millibars across 65 miles) just doesn't fit with the surface obs and wind field.

The observation at the buoy north of the center is very telling, too. Wind is 20 kts blowing AWAY from the center. Can't have development without surface convergence.

[cycloneye]

000
WTNT35 KNHC 072032
TCPAT5
BULLETIN
TROPICAL STORM HENRI ADVISORY NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL102009
500 PM AST WED OCT 07 2009

...HENRI CONTINUING TO WEAKEN...

AT 500 PM AST...2100 UTC...THE CENTER OF TROPICAL STORM HENRI WAS
LOCATED NEAR LATITUDE 19.4 NORTH...LONGITUDE 58.6 WEST OR ABOUT
305 MILES...490 KM...EAST-NORTHEAST OF THE NORTHERN LEEWARD ISLANDS.

HENRI IS MOVING TOWARD THE WEST-NORTHWEST NEAR 15 MPH...24 KM/HR...
AND A TURN TOWARD THE WEST WITH A DECREASE IN FORWARD SPEED IS
EXPECTED TOMORROW.

MAXIMUM SUSTAINED WINDS HAVE DECREASED TO NEAR 40 MPH...65 KM/HR...
WITH HIGHER GUSTS. ADDITIONAL WEAKENING IS FORECAST AND HENRI
COULD DISSIPATE BY THURSDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 105 MILES...165 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB...29.77 INCHES.

...SUMMARY OF 500 PM AST INFORMATION...
LOCATION...19.4N 58.6W
MAXIMUM SUSTAINED WINDS...40 MPH
PRESENT MOVEMENT...WEST-NORTHWEST OR 290 DEGREES AT 15 MPH
MINIMUM CENTRAL PRESSURE...1008 MB

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 PM AST.

$$
FORECASTER BLAKE

000
WTNT45 KNHC 072032
TCDAT5
TROPICAL STORM HENRI DISCUSSION NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL102009
500 PM AST WED OCT 07 2009

HENRI IS WEAKENING THIS AFTERNOON WITH THE LOW-LEVEL CENTER MOVING
EVEN FARTHER AWAY FROM A PERSISTENT AREA OF STRONG CONVECTION. THE
LOW-LEVEL CIRCULATION ALSO IS BECOMING LESS WELL-DEFINED WITH A
SECONDARY CENTER NOTED ON RECENT VISIBLE IMAGES. A BLEND OF THE
TAFB/SAB DVORAK ESTIMATES GIVEN AN INITIAL WIND SPEED OF 35 KT...
BUT THIS COULD BE A LITTLE GENEROUS. STRONG WEST TO SOUTHWEST
SHEAR IS LIKELY FOR A DAY OR SO...WHICH WILL CONTINUE TO WEAKEN THE
CYCLONE. IF HENRI SURVIVES THAT SHEAR...AN UPPER-TROUGH AXIS WITH
CONFLUENT FLOW ALOFT SHOULD PROVIDE THE KNOCKOUT BLOW TO THE
TROPICAL CYCLONE. THE OFFICIAL FORECAST IS BASICALLY AN UPDATE TO
THE PREVIOUS ONE...SHOWING DISSIPATION WITHIN 24 HOURS. HOWEVER...
IF DEEP CONVECTION DOES NOT RETURN NEAR THE CENTER...THIS SYSTEM
COULD BECOME A REMNANT LOW SOONER THAN INDICATED BELOW.

USING A MEAN MOTION OF THE TWO CENTERS...THE INITIAL MOTION IS
290/12. A WEST-NORTHWEST PATH IS PROBABLE FOR THE NEXT DAY OR SO
BEFORE RIDGING BUILDS OVER THE WESTERN ATLANTIC. THIS RIDGE SHOULD
CAUSE HENRI...OR THE REMNANTS THEREOF...TO TURN WESTWARD OR EVEN
SOUTH OF WEST UNTIL THE LOW DISSIPATES. THIS SOLUTION HAS GOOD
SUPPORT FROM MODEL GUIDANCE...AND THE OFFICIAL FORECAST IS CLOSE TO
THE PREVIOUS ONE...REMAINING ON THE SOUTHERN SIDE OF THE GUIDANCE
ENVELOPE NEAR BAM SHALLOW.



FORECAST POSITIONS AND MAX WINDS

INITIAL 07/2100Z 19.4N 58.6W 35 KT
12HR VT 08/0600Z 20.1N 60.3W 30 KT
24HR VT 08/1800Z 20.9N 62.0W 25 KT...REMNANT LOW
36HR VT 09/0600Z 21.2N 63.6W 20 KT...REMNANT LOW
48HR VT 09/1800Z 21.0N 66.0W 20 KT...REMNANT LOW
72HR VT 10/1800Z...DISSIPATED

$$
FORECASTER BLAKE

[gatorcane]

Looks like we have to watch the wave SE of Henri now also. That is looking very impressive and is Caribbean-bound.

viewtopic.php?f=31&t=106794

Henri really hanging in there still (unfortunately).

[wxman57]

I'm not seeing a "second center" the NHC mentions in the advisory. Maybe I'm not holding my head right. Is it about 50-60 miles NNE of the main vortex? If that's what they're looking at, well, I don't know about that. It's racing away from the convection, too. Can't believe they just won't admit that Henri's not a TS. There is no evidence to support TS strength.

[Sanibel]

Those pressures must have sinking air. So there's some sort of mystery synoptic shear out there not only shearing the storms off center but drying them out as well with sick air.


As I've already posted with the numerous other systems like this already this year, we have to watch for the one that beats conditions and forms further west. So far, none have.


(God save my porch screens)

[HURAKAN]

AL, 10, 2009100600, , BEST, 0, 151N, 492W, 30, 1008, TD, 0, , 0, 0, 0, 0, 1012, 150, 30, 0, 0, L, 0, , 0, 0, INVEST, M,
AL, 10, 2009100606, , BEST, 0, 159N, 505W, 35, 1007, TS, 34, NEQ, 45, 0, 0, 0,
AL, 10, 2009100612, , BEST, 0, 169N, 518W, 35, 1007, TS, 34, NEQ, 45, 0, 0, 0, 1012, 120, 45, 0, 0, L, 0, , 0, 0, INVEST, M,
AL, 10, 2009100618, , BEST, 0, 177N, 534W, 35, 1007, TS, 34, NEQ, 45, 0, 0, 0, 1012, 120, 45, 45, 0, L, 0, , 0, 0, HENRI, M,
AL, 10, 2009100700, , BEST, 0, 179N, 546W, 40, 1006, TS, 34, NEQ, 60, 0, 0, 0, 1012, 150, 45, 45, 0, L, 0, , 0, 0, HENRI, M, 12, NEQ, 45, 0, 0, 0
AL, 10, 2009100706, , BEST, 0, 181N, 556W, 45, 1005, TS, 34, NEQ, 60, 20, 0, 0, 1012, 150, 45, 55, 0, L, 0, , 0, 0, HENRI, M, 12, NEQ, 120, 0, 0, 0
AL, 10, 2009100712, , BEST, 0, 186N, 566W, 45, 1007, TS, 34, NEQ, 60, 60, 0, 0, 1014, 150, 45, 55, 0, L, 0, , 0, 0, HENRI, M, 12, NEQ, 180, 0, 0, 90
AL, 10, 2009100718, , BEST, 0, 191N, 578W, 40, 1008, TS, 34, NEQ, 60, 90, 0, 0, 1012, 135, 30, 0, 0, L, 0, , 0,

In the best track it appears now that Henri became a tropical depression on Oct 6 at 00z.



Track

[Aric Dunn]

I'm not seeing a "second center" the NHC mentions in the advisory. Maybe I'm not holding my head right. Is it about 50-60 miles NNE of the main vortex? If that's what they're looking at, well, I don't know about that. It's racing away from the convection, too. Can't believe they just won't admit that Henri's not a TS. There is no evidence to support TS strength.

The problem is is that although you dont see any evidence of TS force winds does not mean that they dont have other sources ..

[HURAKAN]

Latest

It was already a tropical depression when I posted this image.

[Aric Dunn]

Here's an interesting satellite shot/surface plot. Look at the pressure readings and winds around Henri. Note where the highest pressures on the map are - closer to Henri. Now it could be that the ship south of Henri has a barometer that needs recalibration. Look at the pressure gradient from near the center to just east of the heavier squalls - about zero. So there really doesn't appear to be anything present to produce TS winds. Maybe not even 30kt winds. I can't believe that the central pressure of that small vortex is 1008mb. That great of a pressure gradient (8 millibars across 65 miles) just doesn't fit with the surface obs and wind field.

The observation at the buoy north of the center is very telling, too. Wind is 20 kts blowing AWAY from the center. Can't have development without surface convergence.

Also the flat pressure gradient that you seem to see ( lacking any real surface obs to confirm such a thing) could possibly be the presence of the second vort which would disrupt any uniform gradient causing misleading data.

[Aric Dunn]

The overall motion for the last 3 hours has been nearly west .. 270 to 280 maybe.. which should keep it farther south .. and potentially away from the highest shear and sinking air later in the period.

in addition convection should fire very very soon .. the low level cloud deck is thickening more there is some showers starting show just east of the center.

[fci]

I'm not seeing a "second center" the NHC mentions in the advisory. Maybe I'm not holding my head right. Is it about 50-60 miles NNE of the main vortex? If that's what they're looking at, well, I don't know about that. It's racing away from the convection, too. Can't believe they just won't admit that Henri's not a TS. There is no evidence to support TS strength.

Would not be surprised if the 11 PM is the Final Advisory and it is declared a remnant low

[Aric Dunn]

I'm not seeing a "second center" the NHC mentions in the advisory. Maybe I'm not holding my head right. Is it about 50-60 miles NNE of the main vortex? If that's what they're looking at, well, I don't know about that. It's racing away from the convection, too. Can't believe they just won't admit that Henri's not a TS. There is no evidence to support TS strength.

Would not be surprised if the 11 PM is the Final Advisory and it is declared a remnant low

its possible in no convection re fires ///